The duration of battery functionality for multiple cells can be extended through cell balancing. For example, a battery management circuit can include an analog front end that balances the multiple battery cells and eliminates mismatches of cells in a series or parallel combination to substantially improve battery efficiency and increase overall battery stack capacity. For an increasing number of cells and load currents in a battery stack, the potential for mismatch increases for two types of mismatch—state of charge mismatch and the less-common capacity/energy mismatch. Both types of mismatch limit the battery stack capacity (mAh) to the capacity of the weakest cell.